From Ibn Abbas who said the Messenger of Allaah –sallAllaahu alayhi wa sallam– used to seek refuge for al-Hassan and al-Hussein, he would say:

‘I seek refuge for you two with Allaah’s perfect words from every Shaytaan (devil) and poisonous creature and every evil eye.’

He –sallAllaahu alayhi wa sallam– said that this is how Ibrahim used to seek refuge for Ishaaq and Ismaeel.’
[Collected by Bukhari & Tirmidhi with the extra wording, authenticated by Albaani]

An Explanation:

Abul Ulaa AbdurRahmaan al-Mubarakfooree -Rahimullaah- said:

‘Allaah’s words’: ‘It has been said that they are the Qur’aan and it has also been said they are Allaah’s names.’

‘Perfect’: ‘Al-Jazari said: ‘Indeed Allaah’s speech has been described as being Perfect, because it is not permissible for any of His speech to have deficiency or fault like there is in the speech of people.’

‘It has been said that the meaning of ‘Perfect’ here is that it benefits the one seeking refuge with these ‘Perfect words’, and protect him from illnesses and this would be sufficient for him.’

‘Poisonous creature’: ‘Every type of creature that kills with poison. And it is possible that it could mean any crawling animal even if it does not kill, like insects.’

Caller: O Shaykh regarding ‘I seek refuge for you two with Allaah’s perfect words from every Shaytaan (devil) and poisonous creature and every evil eye.’ Is this said three consecutive times or just once?

Shaykh: No, it is mentioned once, however if it appears to the one saying this Dua’ that he needs to repeat it without specifying three times, then there is no problem with that.

Caller: and should he place his hand on the head of the one sought refuge for?

Shaykh: Yes, yes!

Caller: Even in congregation, if it is a group of children together, how can he place his hand upon all of them?

Shaykh: He should place his two hands on two of the children, then repeat this on the rest of the children.